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This study presents for the first time morphometric data from large samples of free-living individuals of Chlamydotis bustards (448 MacQueen's Bustards, 288 African Houbaras, and 53 Canarian Houbaras). Linear measurements were largest in MacQueen's Bustards, intermediate in African Houbaras and smallest in Canarian Houbaras, with differences between the largest and smallest species ranging from 4.5% to 13.9%. Male MacQueen's Bustards were also the heaviest (4% and 15.5% heavier than, respectively, African and Canarian Houbara males) but, unexpectedly, there were no significant weight differences among females of the three bustards. Males of the three bustards were significantly larger than females in all linear measurements and weight. These between-species/subspecies differences are consistent with a slight trend to insular dwarfism that probably selects for smaller size in the Canarian subspecies. Males are larger and heavier than females in the three bustards, as expected in polygynous species, suggesting a moderate effect of sexual selection acting on male size. Finally, the slightly higher sexual size dimorphism values observed in wings and tarsi in MacQueen's bustards compared to both subspecies of African Houbaras are in line with the allometric constraint hypothesis.—Alonso, J.C., Dieuleveut, T., Palacín, C., Abril-Colón, I., Ucero, A. & Lucas, C. (2023). Morphometrics of Houbara Bustards Chlamydotis spp: sexual size dimorphism, seasonal changes and differences between species. Ardeola, 70: 235-247. Este estudio presenta por primera vez datos biométricos de muestras significativas de individuos silvestres de avutardas del género Chlamydotis (448 avutardas de MacQueen, 288 hubaras africanas y 53 hubaras canarias). La avutarda de MacQueen presentó las medidas lineales mayores, con valores intermedios en la subespecie nominal de hubara africana y menores en la subespecie insular canaria, con diferencias del 4,5% al 13,9% entre la primera y la última. Los machos de avutarda de MacQueen fueron también los más pesados (un 4% y un 15,5% respectivamente más que los de hubara africana y canaria), pero no hubo diferencias de peso significativas entre las hembras de las tres avutardas. Los machos de las tres avutardas mostraron un tamaño y un peso significativamente mayores que las hembras. Estas diferencias entre especies y subespecies son consistentes con una ligera tendencia al enanismo insular, que probablemente ejerce una selección hacia un menor tamaño en la subespecie canaria. Los machos fueron más grandes y pesados que las hembras en las tres avutardas, como es esperable en especies poligínicas, lo que sugiere un efecto moderado de la selección sexual sobre el tamaño de los machos. Por último, los valores de dimorfismo sexual ligeramente superiores observados en las alas y los tarsos de las avutardas de MacQueen en comparación con las dos subespecies de hubaras africanas están en consonancia con la hipótesis de la restricción alométrica.—Alonso, J.C., Dieuleveut, T., Palacín, C., Abril-Colón, I., Ucero, A. y Lucas, C. (2023). Biometría de avutardas hubaras Chlamydotis spp: dimorfismo sexual, variaciones estacionales y diferencias entre especies. Ardeola, 70: 235-247. [ABSTRACT FROM AUTHOR]

Variability in morphology and body size between populations of the same species is common and can be influenced by environmental conditions or differential migratory strategies. We focused on analysing body size differences between Yellow-legged gulls Larus michahellis from Mediterranean and Cantabrian-Atlantic Iberian colonies as previous studies have suggested that Cantabrian-Atlantic gulls are smaller than Mediterranean gulls. However, those analyses were based on small sample sizes or did not account for sexual dimorphism. Here we analyse an extensive biometric data set (> 1,500 adult individuals), separating males and females, from nine different sites in each region. Our results reveal a 7% (median) difference both between regions and sexes, for most morphometric variables, with Mediterranean gulls having longer legs (tarsi) and heads (cranium-bill) and thicker bills (bill-depth). This inter-regional difference was even larger for body mass, Mediterranean gulls being 11% (males) and 20% (females) heavier than Cantabrian-Atlantic gulls. In particular, we found that individuals from the Mediterranean populations were allometrically longer-winged than their northern counterparts. We suggest, after discarding other factors, that this wing allometry may be related to the sedentariness of the Cantabrian-Atlantic gulls, compared with the partially migratory strategy of Mediterranean gulls. We also suggest that the larger body size of Mediterranean gulls may help them compete better with resident gulls for food acquisition, once they coincide in the Cantabrian-Atlantic region. Finally, females from both populations were also found to be proportionately longer-winged than males. We hypothesise that this difference could allow smaller females to travel longer distances locally in search of food or to make use of different habitat types, avoiding foraging competition with the larger males.—Marcos Pacheco, M.L., Tavecchia, G., Igual, J.M., Alonso-Álvarez, C., Arizaga, J., Galarza, A., Oro, D. & Martínez-Abraín, A. (2023). Yellow-legged Gulls from the Mediterranean are not only larger but also allometrically longer-winged than those from the Cantabrian-Atlantic. Ardeola, 70: 225-240. La variabilidad en la morfología y el tamaño del cuerpo es común entre poblaciones de la misma especie y puede verse influenciada por las condiciones ambientales o por estrategias migratorias diferenciales. En este trabajo nos centramos en analizar las diferencias de tamaño corporal entre las gaviotas patiamarillas Larus michahellis del Mediterráneo y de las colonias ibéricas cántabro-atlánticas, ya que estudios previos sugirieron un tamaño más pequeño de las gaviotas del Cantábrico/Atlántico en comparación con las gaviotas mediterráneas. Sin embargo, esos análisis se realizaron empleando tamaños de muestra pequeños o no tuvieron en cuenta el gran dimorfismo sexual de la especie. Aquí, analizamos un extenso conjunto de datos biométricos (> 1,500 individuos adultos), separando machos y hembras, de nueve sitios diferentes en cada una de las dos regiones. Nuestros resultados revelaron una diferencia del 7% (mediana) tanto entre regiones como entre sexos, para la mayoría de las variables morfométricas, teniendo las gaviotas mediterráneas patas (tarsos) y cabezas (cráneo-pico) más largos y picos (altura de pico) más gruesos. Esta diferencia entre regiones fue aún mayor en el peso, siendo las gaviotas mediterráneas un 11% (machos) y un 20% (hembras) más pesadas que las gaviotas cántabro-atlánticas. Es importante destacar que los individuos de las poblaciones mediterráneas tuvieron alas alométricamente más largas que sus contrapartes del norte. Sugerimos que esta alometría alar puede estar relacionada con el sedentarismo de las gaviotas cantábrico-atlánticas, frente a la estrategia parcialmente migratoria de las gaviotas mediterráneas, tras descartar otros factores. También sugerimos que el mayor tamaño corporal de las gaviotas mediterráneas podría ayudarles a competir mejor con las gaviotas residentes por la adquisición de alimento, una vez coinciden en la región cántabro-atlántica. Finalmente, también se encontró que las hembras de ambas poblaciones tuvieron alas proporcionalmente más largas que los machos. Proponemos que esa diferencia podría permitir que las hembras (más pequeñas) viajen distancias más largas a nivel local en busca de alimento o hagan uso de diferentes tipos de hábitat, evitando la competencia de forrajeo con los machos más grandes.—Marcos Pacheco, M.L., Tavecchia, G., Igual, J.M., Alonso-Álvarez, C., Arizaga, J., Galarza, A., Oro, D. y Martínez-Abraín, A. (2023). Las gaviotas patiamarillas del Mediterráneo no sólo son más grandes que las cántabro-atlánticas sino que además tienen alas alométricamente más largas. Ardeola, 70: 225-240. [ABSTRACT FROM AUTHOR]

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The authors discuss the results of their study on the moult patterns and body morphometry of pallid swifts Apus pallidus at two locations in northwest Italy from July to October 2014. No significant differences in terms of tail length, tail form depth and wing length between male and female. Moulting started in July and last to nearly five months. During the season, no significant differences in timing and progression were noted between males and females.

The article presents a study which examined the age and sex differences in fuel load and biometrics of aquatic warblers acrocephalus paludicola at an autumn stopover site in the Loire Estuary in the northwest of France. Morphometric traits of 176 individuals captured at the site in relation to age and sex were observed. Significant sex differences in wing length, third primary feather length and body mass, with males being longer winged and heavier than males, were found.

The article discusses a study which examined the sexual dimorphism of the endangered Bonelli's eagle. Topics discussed include the sexual classification of the eagles based on genetic analysis or verification of reproductive behaviour, measurement of biometric variables and the assignment of coloration patterns to plumage parts. Also mentioned are the differences in body length, tarsus width, body mass and hindclaw length.

The article focuses on one study which compares the biometry of Emberiza schoeniclus witherbyi with E. schoeniclus schoeniclus using molecular techniques and discriminant analyses. These birds, which are known as two subspecies of reed bunting Emberiza schoeniclus, were captured in Spain, Portugal and Finland. Their blood, feathers or tissues samples were examined to extract DNA from each group. Discriminant analyses were also applied to identify the best traits for discriminating between the two subspecies. After data analysis, it was revealed that the use bill height only as a simple biometry measurement is enough to distinguish between the two subspecies.

The article focuses on the study which examines the migration strategies of goldfinches Carduelis carduelis as they pass through the western edge of Pyrenees. The study considered the species' time-associated variations in age and sex ratios and morphology. It was carried out through systematic sampling sessions during a specific period. After data analysis, it was revealed that spring migrants showed a shorter wing and tail and were more fuel loaded than birds from autumn and winter. Adults also tended to pass later than juveniles during the autumn season.